Bits described in the above copending applications have included drill bits with a body and a drive shank, the body having spaced prongs in opposite quadrants for supporting the cross cutter and also quadrants for serving as passages for cuttings and dust resulting from the drilling operation, the cuttings entering the drill, in suction type systems, through the openings at the base of the open quadrants and passing through the hole in the drive shank of the drill down into drive steels which are furnishing the rotative power. These bits have had a round cross-section in the lower portion of the body, in some cases reduced from the cross-section of the supporting shanks.
The present invention contemplates a hexagonal portion in the lower part of the body, the supporting quadrants of the bit with a rounded exterior extending upwardly beyond the hexagonal portion to support the tungsten carbide cross insert, and the openings to the interior of the drive shank being made in the empty quadrants intersecting portions of the hexagonal part of the body as well as portions of the open quadrant leading to the hollow part of the drill.
The object of the invention, accordingly, is to provide a hex portion on the bit body which matches the hex portion of a drilling steel to provide a smooth and continuous flow for incoming air which is being drawn up the sides of the drill and which will carry the cuttings down through the center of the drill and the drill steels.
In addition, it is an object of the invention to provide a drill body which, by reason of its shape, improves the air flow in removing the cuttings by a pumping action of the flats and the corners of the hexagonal portion as it rotates, thus preventing the plugging of the drill and the openings.
An additional feature lies in the fact that the head may be gripped with a wrench if necessary for removal from a tool.
Other objects and features of the invention will be apparent in the following description and claims in which the principles of the invention are set forth, together with details which will enable a person skilled in the art to practice the invention, all in connection with the best mode presently contemplated for the invention.